When creating a new photoshop file, there are several different color modes available.
The most common color modes are RBG, CMYK, or Lab modes.
To create a photoshop file in grayscale:
- Create the file as “lab” mode. Image>modes> lab
- In the Channels panel, delete a & b; this will result in one Alpha1 channel
- Create grayscale mode. Image>modes>grayscale
To create a photoshop file in duotone:
- Create the file as “duotone” mode. Image>modes>duotone
- Go into Image>modes>choose the second color.
A duotone is a two-ink color mode. (Two channels in Photoshop and a form of grayscale.) The two inks are usually black plus a pantone but could be any two ink colors.
After a second color is chosen, double click on the graph to determine the white, black, and color ratios.
To create bitmap file:
- Create grayscale, Image>Mode>Grayscale
- Create a “bitmap” mode, Image>Mode>Bitmap
- Choose option; above is “diffusion dither”
Bitmap mode is B/W (actually, black and transparent, depending on how the image is saved.) Bitmaps look textured or speckled, depending ono the settings chosen – this shows diffusion dither.
